Abstract: This paper relocated the 24 June 2012 Ninglang-Yanyuan M_S5.7 earthquake and its aftershock sequence with double-difference earthquake location algorithm. Firstly, we used the cross-correlation technique in time domain to deal with waveform data and got high accuracy differential travel-time data of event pairs. And then we used three different data sets, which are catalog data, waveform cross-correlation data, and catalog data plus waveform cross-correlation data, as the initial data to relocate the Ninglang-Yanyuan earthquake sequence. Comparing the location of main shock, the number of events involved in relocation, the number of events relocated and relocation error for the three data sets, it is suggested that the relocation result of the third data set is the best. The result shows that the original time of the main shock is 15:59:32.74 (Beijing Time) on 24 June 2012, hypocenter location is (27.790°N, 100.707°E), and the focal depth is 10.4 km. Our research also shows that the nearby Yong-ning fault is the seismogenic structure of Ninglang-Yanyuan M_S5.7 earthquake sequence.